The influence of atmospheric turbulence on IM/DD space optical communication system

Lots of researches have simulated performance of optical system based on plane wave or spherical wave model, but optical field is Gauss distribution in real optical communication system. So we derive the relationships between the signal-to-noise ratio (SNR), bit error rate (BER), channel capacity (C) and the transmission distance of the space laser communication system, which is obtained by the Gaussian beam propagation model for on-off keying (OOK) modulated signal under horizontal link. We numerically study the influence of atmospheric turbulence on system performance. we get the conclusions: Under weak turbulence intensity, as the turbulence intensity increases, the C and SNR for OOK modulated space laser communication system decrease while the BER increase; In the case of strong turbulence intensity, the intensity scintillation and the BER dramatically increase with the increase of transmission distance, and then become saturated; In the condition of turbulence intensity and transmission distance are both constant, the longer the wavelength results in greater C, higher SNR and lower BER. Selecting longer communication wavelength can mitigate the impact of the atmosphere turbulence on the communication system in some extent.